Offset drive attachment for tools having rotary driving members



p 1966 E. L. HALL ETAL OFFSET DRIVE ATTACHMENT FOR TOOLS HAVING ROTARY DRIVING MEMBERS 2 Sheets-Sheet 1 Filed Feb. .24, 1964 INVENTORS EMERY L. HAL L.

R/CHARD KOC/A/V BY 6M 6 HTTO Sept. 6, 1966 E. L- HALL ETAL Filed Feb. 24, 1964 2 Sheets-Sheet 2 INVENTORS R 0 HH 4 06 H 4 mm Em L WY/ m B 4 3 United States Patent OFFSET DRIVE ATTACHMENT FOR TOOLS HAV- ING ROTARY DRIVING MEMBERS Emery L. Hall, Hinsdale, and Richard H. 'Kocian, Rolling Meadows, IlL, assignors to Skil Corporation, Chicago,

Ill., a corporation of Delaware Filed Feb. 24, 1964, Ser. No. 346,773 8 Claims. (Cl. 8154) This invention relates generally to attachments for tools having rotary driving members, and more particularly to a new and improved attachment of the type which permits running a fastener from such a tool with the latter in offset relation from the fastener.

The present invention concerns an attachment primarily although not exclusively intended for use with portable power tools of the type having rotary driving members, such as an impact wrench, for example. It is desirable to use such a tool in running fasteners used in the construction of modern day automotive vehicles, for example. Often fasteners in these vehicles are in such confined locations they are inaccessible to impact wrenches and the like because of the bulk of the latter.

Accordingly, there is a need in the art for a lightweight, inexpensive and rugged attachment which will permit a tool, such as an impact wrench, to run a fastener in a rather inaccessible location; the present invention provides such an attachment.

Briefly, the present invention has to do with an offset drive attachment including an elongated body rotatably mounting an input or driven member and a driving or output member at its respective opposite ends for rotation about parallel axes. The driven member includes a cam surface in driving engagement with an arm which extends generally lengthwise of the elongated body. This arm acts as a drive pawl and engages ratchet teeth on the output member. The body also includes a stop pawl in engagement with the rantchet teeth thereby to provide unidirectional rotation of the output member upon oscillation of the drive pawl, which oscillation is brought about by rotation of the driven member. The offset drive attachment also includes unique means adapted to cooperate with means on the nose of an associated power tool thereby to permit the power tool and the offset attachment to be handled and operated together as a unit.

It is a primary object of the present invention to provide an offset drive attachment for a tool having a rotary driving member, which attachment is of new and simplified construction readily lending itself for driving engagement with a fastener located in a rather inaccessible location.

It is another object of the instant invention to provide an attachment of the type described which includes an elongated body rotatably mounting a driven member and a fastener driving member in its respective opposite ends and including improved drive means for transmitting rotation from the 'driven member to the fastener driving member.

Even another object of the invention is the provision of an attachment of the type described for use with a tool having a rotary driving member, wherein the attachment is provided with means adapted to cooperate with complementary means on the tool to prevent relative movement between the attachment and the tool.

Still another object of the instant invention is to provide, in combination, an attachment of the type described and a tool having a nose portion adapted to cooperate with complementary means on the attachment thereby to prevent relative rotation between the tool and the attachment.

These and other objects and advantages of the invention will become apparent from the following specification dis- "ice closing a preferred embodiment of the invention which is illustrated in the accompanying drawings.

In the drawings:

FIG. 1 is a side elevational view of one form of the offset drive attachment of this invention with certain portions being broken away and/ or shown in section for better illustration of the invention;

FIG. 2 is a section taken along line 2-2 of FIG. 1;

FIG. 3 is a fragmentary section taken along line 33 of FIG. 1;

FIG. 4 is an elevational view of the tool attachment and a power tool showing the latter about to be engaged with the driven member of the offset attachment; and

FIG. 5 is an elevational view showing the attachment in driven engagement with the tool of FIG. 4, with certain parts of the latter being broken away and shown in section for better illustration of the engagement between the power tool and the attachment.

Now referring to the drawings, the offset drive attachment of this invention includes a pair of identical elongated plates 10 and 12 held in parallel spaced relation by a number of sleeve-like spacers 14-16 and respective fasteners 1820 which extend through the openings in the spacers and are engaged with the plates. Plates 10 and 12 define the body of the attachment. A driven member 22 includes a pair of cylindrical bearing surfaces 24 and 26 journaled in respective openings 27 and 28 in the plates 10 and 12. Driven member 22 also includes a pair of integral, oppositely extending hexagonal portions 29 and 30, each of which portions is adapted to be non-rotatably received in a complementary shaped driving socket in a tool rotary driving member as will be explained below. Portions 29 and 30 each include annular groove receiving retaining rings 29a and 30a respectively. Finally, driven member 22 includes a central cylindrical portion 32 which has its central axis offset or eccentric with the axis of rotation of member 22 for acting as a cam. Suitable raised annular bearing areas are formed at the juncture of driven member portion 32 and bearing surfaces 24, 26, which bearing areas engage confronting surfaces of plates 10 and 12 around openings 27 and 28 to maintain cyindrical portion 32 in spaced relation from plates 10 and 12 and to secure the driven member against axial movement in the attachment.

An arm 34 is slidably supported between plates 10 and 12, which arm has an enlarged end portion including a cylindrical opening 35 in which is secured an annular bearing member 36. Bearing member 36 snugly but rotatably receives cam portion 32 of driven member 22. It will be apparent that by reason of the eccentric disposition of cam 32, rotation of driven member 22 will result in movement of arms 34 in a generally reciprocal or oscillating manner. The end of arm 34 remote from the end thereof engaged with driven member 22 is in the form of a drive or thrust pawl 38.

A ratchet wheel or fastener driving member, generally designated 40, is rotatably mounted in the end of the drive attachment opposite the end thereof supporting driven member 22; ratchet wheel 40 is mounted for rotation about an axis parallel with the axis of rotation of driven member 22. Referring now to FIG. 1, ratchet wheel 40 includes identical spaced cylindrical portions 41 and 42 rotatably received with respective openings 43 and 44 in plates 10 and 12. Ratchet wheel 40 includes an annular series of ratchet teeth 45 which lie between plates 10 and 12. Ratchet teeth 45 are adapted to be engaged by drive pawl 38 as best seen in FIG. 2 so as to result in clockwise rotation (FIG. 2) of ratchet wheel 40 upon oscillation of the drive pawl, the teeth being adapted to permit overrunning of the drive pawl as the latter is retracted. Ratchet wheel 40 includes a central axially extending, hexagonal shaped opening 46 adapted to receive a complementary shaped fastener or adapter for driving the same.

A stop pawl 48 is disposed between plates and 12 and includes a cylindrical opening 49 at its approximate midpoint, which opening rotat-ably engages spacer sleeve 14. Accordingly, stop pawl 48 is mounted between plates 14 and 12 for rocking or swinging movement about spacer 14. Pawl 48 has one end thereof in the form of a right angle dog 50 adapted to engage ratchet teeth 45 so as to prevent rotation of ratchet wheel 40 in a counterclockwise direction as seen in FIG. 2 and permit rotation of the latter in the opposite direction. A spring 52 has one end thereof engaged in a suitable aperture in pawl 48 adjacent the dog thereof, and the other end of spring 52 is engaged in a suitable aperture in arm 34 adjacent the end thereof defining pawl 38. Manifestly, spring 52 maintains drive pawl 38 and stop pawl 48 in engagement with the ratchet teeth of the ratchet wheel 40.

The end of stop pawl 48 opposite the end thereof including dog 50 is rounded as at 54. Stop pawl 48 includes an integral knob or projection 55 on a side edge thereof adjacent rounded end 54. Knob 55 serves as a means to engage one end of a tool, such as a screw driver,

inserted between plates 10 and 12 thereby to provide a means for rocking stop pawl 48 in a clockwise direction (FIG. 2) so that rounded end 54 thereof engages the side edge of arm 34 thereby todisengage both drive pawl 38 and dog 58 on the stop pawl from the teeth of ratchet wheel 40. The need for freeing the ratchet wheel from the drive and stop pawls will be explained hereinbelow.

A pair of adapter plates 58 and 59 are secured to outside faces of respective plates 10 and 12 adjacent the ends of the latter mounting driven member 22. As adapter plates 58 and 59 are similar in construction, only one plate 58, best illustrated in FIGS. 3 and 4, will be described in detail.

Plate 58 is secured to plate 10 by fasteners 19 and 20 and an additional fastener 61. Fastener 61 extends only through plates 10 and 58 and is flush with the inside face of the former so as not to interfere with movement of arm 34. Plate 58 includes an opening 62 and three raised areas or portions 63, 64 and 65. Plate 58 includes integral, inwardly extending lugs or projections 67, 68, 69 at respective raised portions 63, 64 and 65. By reason of the raised portions of plate 58, lugs 6769 are disposed in parallel and spaced relation from the outer face of plate 10. The purpose and function of these lugs will be explained hereinbelow.

The form of the offset drive attachment illustrated is adapted to be used with a power tool 72 illustrated in FIGS. 4 and 5. Tool 72, which is of the rotary impact type, includes a motor-handle portion '73 containing a suitable motor, such a pneumatic motor, operated by a trigger lever 74. The tool includes an impact clutch portion 75 enclosing a suitable impact clutch mechanism for delivering a series of rotary impact blows to a rotary driving member 76. As seen in FIG. 5, one end of driving member 76 is journaled in a sleeve-like bearing 77 suitably supported in the nose of portion 75 of the tool. Rotary driving member 76 includes a hexagonal shaped socket 79 in the end thereof adjacent the nose of the tool for nonrotatably receiving one of the complementary shaped hexagonal portions 29, 30 of driven member 22 of the offset drive attachment.

According to the present invention, the end of housing portion 75 defining the nose of tool 72 is provided with a plurality of axially extending recesses or grooves 80 to adapt the tool for engagement with the drive attachment. Recesses 88 are equally spaced around the circumference of the nose of the tool and open into the front face of tool 72, i.e. the annular portion thereof surrounding rotary driving member 76. The bases of recesses 80 curve upwardly and join the outer surface of housing portion 75.

The spacing of drive attachment lugs 67-69 is correlated .with the spacing of recesses so that when one of the hexagonal portions 29 or 30 of drive attachment driven member 22 is received in complementary shaped socket 79 of tool driving member 76, the lugs engage a set of three of recesses 80. This engagement between the lugs on the drive attachment and the recesses on the tool prevents swinging or rotation of the drive attachment relative to the tool about the axis of rotation defined by driven member 22 and driving member 76. As there are a greater number of recesses 80 than lugs 67-69, the drive attachment may be fixed to the tool in the manner just described in a number of different angular positions about the axis of rotation of members 22 and 76.

The operation of the offset drive attachment of this invention should be apparent from the above description. The attachment is detachably connected with tool 72 in the manner just described so that upon actuation of tool 72 driven member 22 is rotated thereby providing rotation of ratchet wheel 46 (in a clockwise direction as seen in FIG. 2) when hexagonal portion 29 of driven member 22 is engaged with socket 79 of tool driving member 76. It will be realized that ratchet wheel 40 will be driven in a clockwise direction, as seen in FIG. 2, regardless of the direction of rotation of driven member 22. For this reason, the offset attachment of this invention is designed to be turned over so that hexagonal portion 30 of driven member 22 is driven by the tool driving member thereby to change the direction of rotation of ratchet wheel 40 relative to a fastener. Preferably, plates 10 and 12 are provided with indicia (not shown) on their exterior surfaces adjacent ratchet wheel 42 indicate the direction of rotation of the latter. When the attachment is turned over so that hexagonal portion 30 of driven member 22 is engaged in socket 79 of tool driving member 76, the lugs associated with adapter plate 59 engage recesses 80 of the tool in the same manner as the lugs of adapter plate 58. As mentioned above, hexagonal opening 46 in ratchet wheel 40 is adapted non-rotatably to engage a complementary shaped fastener or adapter for driving the same upon rotation of the ratchet wheel.

Retaining rings 29a, 30a selectively engage the walls of socket 79 of tool driving member 76 so that the offset drive attachment is detachably retained to tool 72. As explained above, the interengagement between the lugs on the adapter plate of the attachment with the recesses of the nose of the tool prevents rotation of the drive attachment relative to the tool. Accordingly, when the offset drive attachment is connected to power tool 72, the latter maybe manipulated by one hand for maneuvering the drive attachment into a confined location so as to reach a fastener and engage the same in hexagonal opening 46 or in an adapter driven by the latter.

It sometimes happens in confined locations wherein a male fastener having a long shank is to be removed, that ratchet wheel 40 in engagement with the head of such a fastener strikes a fixed object before the fastener is completely removed from its associated threaded bore. In such an instance, the pawls of the drive attachment must be released from the ratchet teeth of the ratchet wheel to allow the fastener to be run, as by hand for example, back into its associated opening a short distance to provide sufiicient clearance between the head of the fastener and-the fixed object thereby to allow removal of the drive attachment. The pawls of the drive attachment of this invention may be separated from the teeth of the ratchet wheel for freeing the latter by inserting a screw driver or the like between plates 10 and 12 and into engagement with the end of the stop pawl including knob or projection 55. Forcing a screw driver between plates 10 and 12 in this manner causes stop pawl 48 to rock (in a clockwise direction as seen in FIG. 2) thereby freeing dog 50 from ratchet teeth 45 and causing rounded end 54 of the stop pawl to engage arm 34 thereby to free drive pawl 38 from the ratchet teeth. Knob or projection 55 on the stop pawl prevents the tip of a screw driver or the like from slipping along the side edge of the stop pawl.

It should be noted that by reason of the shape of drive pawl 38 and ratchet teeth 45, the former does not have to swing outwardly or away from the teeth a substantial distance during the retracting stroke of arm 34. This feature permits the end of the attachment supporting ratchet wheel 40 to be smaller in size thereby facilitating entry of this end of the attachment into rather confined locations.

It should be realized that the offset drive attachment of this invention is well suited for use with a power tool of the rotary impact type which delivers in rapid succession a series of rotational impact blows. The offset drive attachment efficiently transfers impact blows from such a power tool to a fastener since there is little if any energy absorbing slop or backlash movement in the ratchet and pawl drive of the attachment as is true in some forms of drive attachments.

While the invention has been shown in but one form, it will be obvious to those skilled in the art that it is not to be so limited. On the contrary, the invention is susceptible of various forms and modifications without departing from the spirit and scope of the appended claims.

We claim:

1. An offset drive attachment for a tool of the type having a rotary driving member, said attachment comprising, an elongated body, a driven member rotatably mounted in one end of the body and adapted to be driven by said driving member, said driven member in cluding a cam surface eccentric with respect to the axis of rotation of the driven member, an arm carried by said body for movement in a plane perpendicular to said axis, said arm having drive pawl means associated with one end thereof and having the other end thereof engaged with said cam surface so that rotation of said driven member brings about oscillating movement of the drive pawl means, a ratchet wheel adapted to engage a rotary member for driving the same, which ratchet wheel is rotatably mounted in the other end of said body and has teeth engaged by said pawl means, stop pawl means carried by the body and engaged with the ratchet wheel teeth to prevent rotation of the ratchet wheel in one direction, and means carried by the body for holding said drive pawl means in engagement with the teeth on the ratchet wheel so that upon rotation of the driven member the ratchet wheel is rotated in a direction opposite said one direction.

2. The attachment according to claim 1 wherein said stop pawl upon being disengaged from the ratchet teeth is adapted to contact said arm for disengaging the drive pawl means from the ratchet teeth thereby to free the ratchet wheel from both pawls.

3. An offset drive attachment for a tool of the type having a rotary driving member, said attachment comprising, an elongated body, a driven member rotatably mounted at one end of the body and adapted to be driven by said driving member, which driven member includes a cylindrical cam surface eccentric with respect to the axis of rotation of the former, an arm carried by said body for movement in a plane perpendicular to said axis, said arm having a circular opening in one end thereof rotatably receiving said cam surface and said arm having the other end thereof in the form of a drive pawl, a ratchet wheel adapted to engage a rotary member for driving the same, which ratchet wheel is rotatably mounted to the other end of said body and has its teeth engaged by said drive pawl, stop pawl means carried by the body and engaged with the ratchet wheel teeth to prevent rotation of the ratchet wheel in one direction, and resilient means carried by the body for holding said drive pawl in engagement with the teeth on the ratchet wheel so that upon rotation of the driven member the ratchet wheel is rotated in a direction opposite said one direction.

4. An offset drive attachment for a tool of the type having a rotary driving member, said attachment comprising, an elongated body consisting of two plates closely secured together in parallel spaced relation, a driven member rotatably mounted in one end of the body and adapted to be driven by said driving member about an axis perpendicular to said plates, which driven member includes a cylindrical cam surface eccentric with respect to said axis and disposed between said plates, an arm slidable between said plates and having a circular opening in one end thereof rotatably receiving said cam surface, said arm having the other end thereof in the form of a drive pawl, a ratchet wheel adapted to engage a rotary member for driving the same, which ratchet wheel is rotatably mounted in the other end of said body for rotation about an axis parallel with said axis, said ratchet wheel having the teeth thereof disposed between said plates and engaged by said drive pawl, stop pawl means carried between said plates and engaged with the ratchet wheel teeth to prevent rotation of the ratchet Wheel in one direction, and resilient means carried between said plates for holding said drive pawl in engagement with the teeth on the ratchet wheel so that upon rotation of the driven member the ratchet wheel is rotated in a direction opposite said one direction.

5. An oifset drive attachment of the type having a rotary drivin-g member, said attachment comprising, an elongated body consisting of two plates closely secured together in parallel spaced relation, a driven member rotatably mounted in one end of the body and adapted to be driven by said rotary driving member about an axis perpendicular to said plates, which driven member includes a cylindrical cam surface eccentric with respect to said axis and disposed between said plates, an arm slidable between said plates and having a circular opening in one end thereof rotatably receiving said cam surface, said arm having the other end thereof in the form of a drive pawl, a ratchet wheel adapted to engage a rotary member for driving the same, which ratchet wheel is rotatably mounted in the other end of said body for rotation about an axis parallel with said axis, said ratchet wheel having the teeth thereof disposed between said plate and engaged by said drive pawl, a stop pawl disposed between said plates and extending in general parallel relation with said arm, which stop pawl is pivotally mounted intermediate its ends, one of which ends is in the form of a dog engaging said ratchet teeth to prevent rotation of the ratchet wheel in one direction, resilient means engaging the drive pawl and the stop pawl at the end of the latter adjacent the dog for holding both pawls in engagement with the ratchet teeth so that upon rotation of the driven member the ratchet wheel is rotated in a direction opposite said one direction, disengagement of the pawls from the ratchet wheel teeth being accomplished by inserting a slender tool between said plates and into engagement with the other end of the stop pawl so as to rock the latter thereby freeing the dog from the ratchet teeth and bringing said other end in contact with said arm thereby freeing the drive pawl from the teeth.

6. In combination, a tool having a non-rotatable housing nose supporting a rotary driving member, which nose is provided with at least one recess in the exterior thereof, a drive attachment detachably engaged with said tool for transmitting rotation from said rotary driving member to rotary fastening means wherein the axis of rotation of the latter is parallel and substantially spaced from the axis of rotation of the former, said attachment including an elongated body supporting a driven member and a fastener driving member at its respective opposite ends for rotation about spaced parallel axes, said driven mem ber being detachably connected with said rotary driving member for being driven by the latter and said fastener driving member being adapted for driving engagement with rotary fastening means, drive means carried by said body for transmitting rotation of said driven member to said fastener driving member, and at least one lug on 7 said body in engagement with said recess for preventing rotation of the attachment relative to the tool about the rotational axis of the rotary driving member, whereby said tool and said attachment may be handled and operated together as a unit.

7. In combination, a tool having a housing nose supporting a rotary driving member, which nose is provided with at least one recess in the exterior thereof, a drive attachment detachably engaged with said tool for trans mitting rotation from said rotary driving member to rotary fastening means wherein the axis of rotation of the latter is parallel and substantially spaced from the axis of rotation of the former, said attachment including an elongated body, a driven member rotatably mounted in one end of the body and detachably engaged with said rotary driving member for being driven by the latter, said driven member including a cam surface eccentric with respect to the axis of rotation of the driven member, an arm carried by said body for movement in a plane perpendicular to said axis, said arm having drive pawl means associated with one end thereof and having the other end thereof engaged with said cam surface so that rotation of said driven member brings about oscillating movement of the drive pawl means, a ratchet wheel adapted to engage 25 means carried by the body and engaged with the ratchet wheel teeth to prevent rotation of the ratchet wheel in one direction, and means carried by the body for holding said drive pawl means in engagement with the teeth on the ratchet wheel so that upon rotation of the driven member the ratchet wheel is rotated in a direction opposite said one direction.

8. The combination according to claim 6 wherein said housing nose includes a plurality of said recesses in a circumferentially spaced pattern and wherein said attachment includes a corresponding number of said lugs in a complementary pattern and in snug frictional engagement in respective recesses.

References Cited by the Examiner UNITED STATES PATENTS 2,600,177 6/1952 Able et a1. 8161 X 2,672,065 3/1954 Danuskie 8157 2,817,256 12/1957 Malone et a1 8157 3,041,902 7/1962 Wing 8156 3,191,465 6/1965 Parker 81--53 X FOREIGN PATENTS 144,289 11/1951 Australia.

WILLIAM FELDMAN, Primary Examiner.

JAMES L. JONES, JR., Examiner. 

1. AN OFFSET DRIVE ATTACHMENT FOR A TOOL OF THE TYPE HAVING A ROTARY DRIVING MEMBER, SAID ATTACHMENT COMPRISING, AN ELONGATED BODY, A DRIVEN MEMBER ROTATABLY MOUNTED IN ONE END OF THE BODY AND ADAPTED TO BE DRIVEN BY SAID DRIVING MEMBER, SAID DRIVEN MEMBER INCLUDING A CAM SURFACE ECCENTRIC WITH RESPECT TO THE AXIS OF ROTATION OF THE DRIVEN MEMBER, AN ARM CARRIED BY SAID BODY FOR MOVEMENT IN A PLANE PERPENDICULAR TO SAID AXIS, SAID ARM HAVING DRIVE PAWL MEANS ASSOCIATED WITH ONE END THEREOF AND HAVING THE OTHER END THEREOF ENGAGED WITH SAID CAM SURFACE SO THAT ROTATION OF SAID DRIVEN MEMBER BRINGS ABOUT OSCILLATING MOVEMENT OF THE DRIVE PAWL MEANS, A RATCHET WHEEL ADAPTED TO ENGAGE A ROTARY MEMBER FOR DRIVING THE SAME, WHICH RATCHET WHEEL IS ROTATABLY MOUNTED IN THE OTHER END OF SAID BODY AND HAS TEETH ENGAGED BY SAID PAWL MEANS, STOP PAWL MEANS CARRIED BY THE BODY AND ENGAGED WITH THE RATCHET WHEEL TEETH TO PREVENT ROTATION OF THE RATCHET WHEEL IN ONE DIRECTION, AND MEANS CARRIED BY THE BODY FOR HOLDING SAID DRIVE PAWL MEANS IN ENGAGEMENT WITH THE TEETH ON THE RATCHET WHEEL SO THAT UPON ROTATION OF THE DRIVEN MEMBER THE RATCHET WHEEL IS ROTATED IN A DIRECTION OPPOSITE SAID ONE DIRECTION. 